#include <stdio.h>

int f(int x, int y) {
    if (x == 0 && y == 0)
        return 0;
    if (x == 0 || y == 0)
        return 1;
    return f(x-1, y) + f(x, y-1);
}

int main()
{
    int x=0, y=0;
    scanf("%d%d",&x,&y);
    if (x > 10 || x < 1 || y > 10 || y < 1)
        return -1;
    int ans = f(x, y);
    printf("%d",ans);
    return 0;
}
